Another way of putting it: a god who can't figure out to stop a species that he designed and created from proliferating out of control without inflicting diseases on them with is rather uncreative or incompetent. I mean, if that prospect worries god, why would he build the problem into our "design" in the first place?Sorry, Penguin. I'm not following you here.
Basically, it seems to me that you're suggesting that God needs mosquitos to correct a problem that, presumably, God himself created. Either that or God can't figure out a way to solve the problem without waging biological warfare on his creation.
I think this point of view has theological implications that don't mesh well with the beliefs of many religions.